I wonder if spin-lock hurts hyperthreading.
On Sat, Aug 11, 2012 at 7:22 PM, Hideki Kato <hideki_ka...@ybb.ne.jp> wrote: > Petr Baudis: <20120811145900.gv19...@machine.or.cz>: >>On Sat, Aug 11, 2012 at 12:52:12AM -0700, David Fotland wrote: >>> Yes, root parallelization with some sharing. >>> http://www.personeel.unimaas.nl/G-Chaslot/papers/parallelMCTS.pdf said it >>> was good and I tried it and it works well. >> >>The paper is not so relevant now, since the standard method of most >>programs is lockless tree parallelization, which is not covered. >>The locking overhead is quite significant, I'd expect, as locking >>instructions can AFAIK take hundreds of cycles. > > With spin-lock or hardware test-and-set instructions, locking overhead > is very small. > >>That said, root parallelization overperforming sequential simulations >>is something I never managed to reproduce and that seems rather >>surprising to me. It might have something to do with the way priors >>are done in the tree or some other engine-specific factors. > > I believe IBM Power processor's architecture may caused the super-linear > acceralaton. > > Hideki > -- > Hideki Kato <mailto:hideki_ka...@ybb.ne.jp> > _______________________________________________ > Computer-go mailing list > Computer-go@dvandva.org > http://dvandva.org/cgi-bin/mailman/listinfo/computer-go _______________________________________________ Computer-go mailing list Computer-go@dvandva.org http://dvandva.org/cgi-bin/mailman/listinfo/computer-go
